The present invention relates to clearance measurement systems, a clearance measurement vehicle and a method for performing clearance measurement calculations.
Most of the clearance measurement systems utilized by U.S. and Canadian railroads are very antiquated and were created as many as 30 years ago. Several railroads do not own clearance measurement systems and employ contractors to provide the structural data at a costly price. A clearance measurement system is basically designed to ensure that a particular size of railway car load can travel along its intended track section.
The assignee of the present invention previously developed a clearance vehicle which rides along a railroad track by means of a rail guide attachment. The vehicle also includes a mercury bulb mounted on an "A" frame in front of the vehicle and a 35 mm camera mounted on top of the vehicle. As the vehicle travels along the track, it takes still photographs at various locations to record any obstructions present alongside and over the track. The photographs are enlarged to the required scale and an obstruction outline is plotted on clearance diagrams. These clearance diagrams are used by specialized personnel called "clearance engineers" to determine routing of shipments of excessive height and/or width.
Prior to development of the photographic system described above, a "finger car" was used for obtaining clearances. The finger car was moveable along the railroad track and included a vertically extending inverted U-shaped frame with rods (fingers) extending outwardly from the frame. Each rod, or finger, required reading to determine the amount of bend caused by touching various obstructions. This method was fairly precise, but required several workers.
According to the previously used photographic method and finger car method, a hand drawn clearance diagram was used to determine if a customer's unusually large shipment would safely pass the structures adjacent to the railroad track. These systems require too much manpower and take too much time to complete a clearance measurement. Accordingly, a need exists in the art for a clearance measurement system which requires less manpower and which can be performed in an efficient manner. Furthermore, the movement of dimensional shipments is growing approximately 30% each year necessitating a more efficient and accurate measurement system. Such an improved system would be a major breakthrough for the clearance measurement process for all railroads.
The photographic system utilizes a Chevrolet Suburban highrail vehicle having a 35 mm camera mounted to the top of it. In front of the vehicle, an intense light beam is emitted in a circular pattern perpendicular to the direction of movement. This light beam or plane is approximately eighteen feet measured horizontally from the camera. The vehicle measures clearances after dark. As the vehicle travels down the tracks, the operator stops the vehicle when the light beam illuminates structures adjacent to the track and a photograph is taken. In view of the fact that the camera is located a certain distance from the light beam, the diagram scale is constant. The film is later developed and placed on a view graph machine so that the structure can be drawn on a piece of mylar and a clearance diagram can be produced.
Accordingly, it is an object of the present invention to provide a new clearance measurement system. Such a new system should provide an increased amount of data, facilitate the assessment of moving a specific reference object along the path, improve the ability to alter certain structures to permit clearance, and numerous other objects will be apparent from the following.
According to the present invention, a clearance control system is provided for measuring clearances at locations which are spaced apart along a path of movement. The system includes a vehicle moveable along the path of movement, radiation transmitting means supported on the vehicle for providing a beam of energy which reflects off portions of outer peripheries of obstacles and recording means for recording signals corresponding to coordinates of the obstacles.
The recording means is supported by the vehicle in fixed relationship thereto such that the recording means can continuously record the signals while the vehicle moves along the path of movement. The recording means receives reflections of the beam of energy off the portions of the outer peripheries of the obstacles and the signals recorded by the recording means correspond to coordinates of the portions of the outer peripheries of the obstacles.
The system preferably includes moveable support means for moving the recording means between first and second spaced-apart positions. The first position corresponds to a predetermined location at which the recording means can record the signals. The second position corresponds to a location at which the moveable support means can be stored while the vehicle travels from one clearance measurement site to another clearance measurement site.
The system preferably includes means for receiving the signals from the recording means and for storing data corresponding to coordinates of the obstacles. The system can further include means for determining whether a reference object will pass freely along the path of movement without hitting any of the obstacles. The determining means can comprise a clearance diagram or computerized clearance software.
According to the preferred embodiment, the recording means comprises a video camera and the means for receiving the signals comprises data storage means for storing data continuously received from the video camera. The data corresponds to graphic coordinates of obstacles along the path of movement. The data also represents structural coordinates of the obstacles in relation to at least one fixed reference point at various locations along the path of movement. The data storage means can include a data disk on which graphic files are stored. The data is preferably in digitized form and data processing means comprising clearance program software can also be used to perform calculations using the data to determine whether the reference object will pass freely along the path of movement without hitting any of the obstacles.
The inventive system preferably includes a monitor for displaying an image corresponding to the data at a selected location along the path of movement. A data display computer can be provided for overlaying information on the videotape.
According to the preferred embodiment, the path of movement comprises a railroad track and the obstacles comprise obstructions located adjacent to the railroad track. The vehicle can include one or more reference points within the field of view of the video camera. The video tapes can be stored at a single location. A clearance engineer uses the videotapes to determine whether a reference load can be carried by a train safely along a particular route on the railroad track. This determination can be performed using clearance diagrams or by computerized clearance software adapted to process the recorded data representing coordinates of obstacles located along the railroad track and data representing the reference load.